Curl.EXE Execution With Custom UserAgent

A Sigma rule for process creation on Windows, from SigmaHQ’s threat hunting rules, by frack113.

medium 1 ATT&CK technique 1 program it names

What it looks for

its detection, as SigmaHQ writes it

detection:
  selection_curl:
    - Image|endswith: '\curl.exe'
    - Product: 'The curl executable'
  selection_opt:
    CommandLine|contains:
      - ' -A '
      - ' --user-agent '
  condition: all of selection_*

The rule’s detection, its selections and fields in order of name. The whole rule, with its references and false positives, is on SigmaHQ, by frack113, under the Detection Rule License 1.1. CmdID evaluates it on a command line alone: a test on what a command line cannot show, such as the parent process or the user, is not met.

None of the everyday examples and documented commands on CmdID’s program pages trips it. To see whether a command line does, paste it into CmdID.

Programs and files it names

their pages here

curl.exe

ATT&CK

the techniques it is tagged with

T1071.001Application Layer Protocol: Web Protocols

Curl.EXE Execution With Custom UserAgent

What it looks for

Programs and files it names

ATT&CK

Other rules for T1071.001 Application Layer Protocol: Web Protocols